As you know, water evaporates from coils and curls super quickly. If you don’t seal in moisture after washing your hair, you could end up with bone dry strands in less than an hour. To help your hair retain moisture, choose one of these oils that stand out from the rest because of their proven sealing power.
1) Mineral oil, also known as paraffinium liquidum, is the most effective oil for sealing moisture into the hair or skin. It’s obtained from drilling into the earth, which sounds nice, but everything that comes straight from the ground (including water), is actually pretty dirty. The Food and Drug Administration requires mineral oil to be refined and purified to remove impurities before it can be used in cosmetics or pharmaceuticals. Mineral oil works best to increase moisture retention because it’s made of hydrophobic/water insoluble compounds. That means when you seal with mineral oil, the water that absorbed into your hair when you washed has to work hard to escape past the “barrier” or “seal”. It will still get out (i.e. your hair will still become dry) but it will happen much more slowly than if the mineral oil wasn’t there. The downside of mineral oil is that it can leave a greasy feel.
2) Silicone oil aka dimethicone
Silicone is a type of synthetic oil made in science laboratories using silicon (a naturally occurring element found in sand) and oxygen. Dimethicone is a type of silicone that is used in different molecular weights. Higher weight dimethicone is thick and sticky and it’s used for industrial applications like sealing moisture away from bathroom tiles and walls. Lower molecular weight dimethicone is thin and it spreads easily; it’s used in personal care products to seal in moisture on the skin and hair. The silicon and oxygen in dimethicone make it slightly more water soluble than mineral oil which means it won’t help your hair stay moisturized for quite as long. The advantage that dimethicone has over mineral oil is that it’s more resistant to being rinsed off (but it washes off with sulfate-free cleansers) and it gives the hair a little bit more shine.
3) Shea Oil
Shea oil is the liquid form of shea butter and they both come from the nuts of the shea tree. The natural fatty acids in plant oils make them more water soluble than mineral oil and dimethicone which means they don’t create an effective “moisture gate”. Water will evaporate from your hair faster when you seal with shea oil (or butter) compared to mineral oil or dimethicone. However, of all plant oils, shea can trap the most moisture because it contains allantoin, a unique natural component that helps keratin cells hold on to water molecules. Shea oil will help your hair retain moisture but it’s less effective and more expensive than dimethicone and mineral oil.
Even the best sealing oils do not prevent moisture from escaping from your hair’s cortex, they just slow down how quickly moisture escapes. Next time you reach for a moisturizing product or head for the shower to wash your hair, take a moment to realize that water escaped from your hair despite your best efforts to keep it in. Your hair dries out even faster than your skin! The best strategy to combat dry hair is to re-moisturize at the first sign of dryness, even if that means every day. Seal in moisture with mineral oil, dimethicone, or shea oil to keep your hair smooth, soft, and shiny between washes.